Fluid-actuated contraction drive and associated contraction tube

ABSTRACT

A fluid power contractile drive comprising a contractile hose ( 2 ), which on fluid actuation of an actuation space ( 7 ) delimited by it undergoes longitudinal contraction and which at its two terminal regions ( 5  and  6 ) is adapted to be, or is, provided with a force output means ( 8 ) rendering possible output of the drive force produced. At one terminal region ( 5  and  6 ) at least the contractile hose ( 2 ) possesses a flat configuration and is bent over, the hose sections ( 18  and  19 ) of the hose sections being placed adjacent to each other owing to such bending over being connected firmly with each other.

The invention relates to a fluid power contractile drive comprising acontractile hose, in the case of which when there is a fluid actuationof an actuation space delimited by it a longitudinal contraction thereoftakes place and which at its two terminal regions is adapted to be, oris, provided with a force output means rendering possible output of thedrive force produced. Furthermore, the invention relates to acontractile hose for a fluid power contractile drive.

The patent publication WO 00/61952 A1 and the European patentpublication 0 161 750 B1 each disclose a fluid power contractile drive,which comprises a contractile hose, which at its end has a force outputmeans attached to it. The contractile hose comprises a rubber elastichose body and a tensile fiber arrangement coaxial to it. If theactuation space delimited by the contractile hose is filled with a fluidpressure medium subject to a certain operating pressure, the contractilehose will be subject to a radial spread accompanied by an axiallongitudinal contraction. Accordingly tension forces will be exerted onthe force output means so that same are acted upon to produce a mutualmovement toward one another. It is in this manner that externalstructures and components, which are secured to the force output means,may be braced together and/or moved in relation to one another.

More particularly in the case of actuation with a high operatingpressure it is a problem to ensure a reliable seal and a reliabletransmission of force at the terminal regions to the force output means.Accordingly one object of the present invention is to provide a fluidpower contractile drive and a contractile hose for a fluid powercontractile drive, in the case of which such problems no longer occur orare at least less severe.

This object is to be achieved in the case of a fluid power contractiledrive of the type initially mentioned since the contractile hose has aflat configuration at least at one terminal region and is bent over, thehose sections arranged adjacent to each other owing to the bending ofthe hose sections of the contractile hose being firmly connected witheach other.

Moreover the object is attained in the case of a contractile hose of thetype initially mentioned which is characterized in that at one terminalregion at least it has a flat configuration and is bent over, the hosesections, arranged adjacent to each other owing to the bending, beingfirmly connected together.

Owing to the bending over of the respective terminal region of thecontractile hose in conjunction with the flat configuration thereof thehose ends may be extremely simply and reliably sealed. More especiallyat the point of bending over a reliable seal may be produce owing to thechange in direction. However by thrusting the oppositely placed parts ofthe hose wall together it is also possible to encourage a reliablesealing action. At any rate the bent over terminal region is highlysuitable for reliably anchoring a force output means rendering possiblethe output of the drive force produced.

Further advantageous developments of the invention are defined in thedependent claims.

Preferably the adjacently placed hose sections make flat contact witheach other, same being more particularly firmly thrust together.

The firm connection of the adjacently placed hose sections may forexample be produced by a bond, a weld or a sewn joint, although howeverpining together of the hose sections using at least one connection pin,extending through them, is possible as well. These types of connectionmay be combined with each other in any desired way.

At least one connecting pin present, for instance in the form of a screwor a rivet, can also be a component of the associated force output meansor constitute same. In this connection it is an advantage if at leastone pin has a screw thread, which may be secured to the structure to bebraced or moved or, respectively, as part of a screw connection.

The contractile hose preferably consists of a hose body with rubberelastic properties, in whose wall a tensile fiber arrangement iscoaxially embedded. The tensile fiber arrangement may also be seated atthe outer periphery of the hose body. Preferably, the tensile fiberarrangement consists of a plurality of crossed over tensile fibershaving a high tensile strength and also flexible properties. Owing tothe flexibility the bending over of the contractile hose is not hinderedat the respective terminal region.

In the following the invention will be described with reference to theaccompanying drawings in detail.

FIG. 1 is a longitudinal sectional representation of a preferred firstdesign of the contractile drive in accordance with the invention.

FIG. 2 is a perspective elevation on a larger scale of the portionmarked II in FIG. 1 of the contractile drive.

FIG. 3 shows a terminal section of an alternative design of thecontractile drive, again in a perspective view.

The drawing shows a fluid power contractile drive generally referenced1. It may be operated by a liquid or more preferably with a gaseousmedium.

An important part of the contractile drive 1 is a hose-like membraneelement referred to 2, which consists essentially of a hose body 3 ofrubber elastic material and a tensile fiber arrangement 4 arrangedcoaxially in relation to the hose body. The tensile fiber arrangement 4may surround the hose body like a stocking. It is preferably embedded inthe wall of the hose body so that together with it constitutes ahose-like component.

At its two terminal regions 5 and 6 the contractile hose 2 is sealed offin a fluid-tight manner. Accordingly it delimits an elongated actuationspace which is hermetically sealed off from the surroundings.

At each terminal region 5 and 6 a force output means 8 is secured. Sameis provided with force output means 12 with which structures to bebraced together or to be moved may be directly or indirectly secured. Inthe case of the working examples the force output means 12 areconstituted by one or more threads, which render possible a screwattachment of the above mentioned components.

In the deactivated initial state, which is illustrated in full lines inFIG. 1, the force output means arranged at the two terminal regions 5and 6 are at the maximum distance apart. The contractile hose 2possesses a certain initial length. The actuation space 7 is free ofpressure.

For the activation of the contractile drive 1 the actuation space 7 isfilled with a fluid pressure medium subject to predetermined actuationpressure. This pressure medium may be supplied by way of a fluid duct 13communicating with the actuation space 7. In the working embodiment thesupply of the fluid takes place through the wall of the hose body 3,which for this purpose is provided with suitable connection means 14. Itwould however also be possible to produce, more particularly in the caseof a gas-powered contractile drive, the drive gas in the interior of theactuation space using a pyrotechnical means (not illustrated).

On activation the actuation space 7 is acted upon by an interiorpressure so that contractile hose 2 is spread out radially. This radialspread is accompanied by an axial shortening of the hose length.Accordingly the force output means 8 are pulled together.

The cause of this behavior is the particular structure of thecontractile hose 2, more particularly in conjunction with the abovementioned tensile fiber arrangement 4. The tensile fiber arrangement 4has, in the working embodiment, a plurality of tensile fibers which areseparate or arranged in strands, and which are crossed over orreticulated. In the radial direction as related to the longitudinal axis15 of the contractile drive 1, the tensile fiber arrangement moreparticularly constitutes a grid-like structure. In the case of theradial spread or widening of the hose body 3 the grid angles change sothat owing to contractile hose 2 a tension force is engendered at theterminal regions 5 and 6. Such tension force, whose direction isindicated by arrows 16, is transmitted to the force output means 8 by anon-positive or a positive coupling effect, such means accordinglymoving toward each other in the direction 16 of the tension force. Theactivated condition produced in this fashion is indicated in chainedlines in FIG. 1 at 17.

The contractile hose could also have a different structure in order toproduce a different operational characteristic.

During actuation the structures and/or components secured to the forceoutput means 8 are shifted in relation to each other so that the desiredeffect is produced.

The contractile hose 2 is characterized by having a customized orspecially adapted form of its terminal regions 5 and 6. This will beexplained in more detail with reference to the terminal region 5depicted on the left in FIG. 1. The other terminal region 6 ispreferably identically designed. However, there is also the possibilityof only designing one of the terminal regions with this particularconfiguration.

The above particulars and the following particulars also apply for themodified design illustrated in FIGS. 2 and 3 unless anything is said tothe contrary.

The contractile hose 2 has a flat shape at its terminal region 5. Thisform is more particularly produced by squeezing the contractile hose 2,originally having a circularly cylindrical configuration, from eitherside at its terminal region so that diametrally opposite hose wallsections 11 a and 11 b have their inner faces thrust against each otherpreferably over large areas.

At the said terminal region 5 the contractile hose 2 is bent over. Theline 22 of bending or folding indicated in chained lines in FIGS. 2 and3 extends at a right angle to the longitudinal axis 15 and at the sametime in parallelism to the plane of extent of the flat terminal region5. It could be said that the respective terminal region 5 of thecontractile hose 2 is bent back.

There is at least one folded back part, and preferably there is only onesuch fold. In any case such folding over means that at least two hosesections 18 and 19, each with a flat configuration, of the terminalregion 5 assume positions adjacent to each other, preferably with aparallel alignment. These hose sections 18 and 19 are firmly connectedtogether by suitable means.

Preferably the hose sections 18 and 19, of which in the working examplethere are two, produced by folding or bending over make flat engagementwith one another at the facing sections of the outer faces. Thepreferably at least substantially plane zone of contact is identified byreference numeral 23 in FIGS. 2 and 3.

Owing to such direct at the fold 24 a sharp bend is produced in thelongitudinal extent of the contractile hose 2. The bend means that thecontractile hose 2 is pinched and sealed in a fluid-tight fashion sothat the desired sealing off of the actuation space 7 from thesurroundings is ensured.

In order to hold the structure in the bent over position in the case ofthe design in accordance with FIG. 2 the adjacent hose sections 18 and19 are bonded together in the zone 23 of contact. Alternatively a weldjoint would be possible.

In the working embodiment illustrated in FIG. 3 instead of a bond and/orweld there is a sewn connection or seam 25. Using suitable stitchingmeasures with at least one sewing thread with a sufficient tensilestrength in this case the two adjacent hose sections 18 and 19 arefirmly sewn together. The seam extends through the zone 23 of contactathwart the longitudinal direction 15 of the contractile drive 1.

In addition an adhesive can be applied at the terminal region 5 in theinterior of the contractile hose so that the mutually engaging wallareas of the contractile hose 2 are also bonded together in the interiorin order to further optimize the seal and the coherence of thestructure.

It is in this case an advantage if the hose sections 18 and 19, arrangedadjacent to each other owing to bending over (and which in the workingexample are on top of each other) are firmly pressed together. Suitableclamping means for this purpose may be the sewing thread or threadspossibly employed for the seam 25.

In all working embodiments illustrated the mutual pressing together ofthe adjacent hose sections 18 and 19 is produced exclusively oradditionally by at least one connecting pin or bolt 26, which acts onthe adjacently placed hose sections 18 and 19 athwart their longitudinaldirection and by way of suitably shaped clamping heads 27 acts on theside faces 28 and 29 directed away from the area 23 of contact. In FIG.3 only the clamping head 27 placed on the side face 28, which isdirected upward.

The at the least one connecting pin 26 can be a screw or a compressionrivet, the clamping heads 27 being constituted by the heads of suchconnecting elements.

FIG. 2 shows a design having a plurality of connecting pins 26 on therespective terminal region 5. Unlike this in the case of the workingembodiment of FIG. 3 only one such connecting pin 26 is provided on therespective terminal region 5.

The connecting means described for mutually securing the hose sections18 and 19 provided by the bending over or folding operation may beprovided respectively separately or in combination with each other.

In all working embodiments the connecting pins 26 arranged at therespective terminal region simultaneously constitute the force outputmeans 8. Since the connecting pins 26 extend through the hose sections18 and 19 athwart the direction 16 of the tension force, there is anoptimum interlocking or positive connection and accordingly reliableforce transmission between the contractile hose 2 and the force outputmeans 8. The force output means 12 may in this case be in the form ofscrew threads, which render possible a screw attachment of the structureor components which are to be braced and/or shifted.

Owing to the bending over technique there is furthermore a certainself-braking effect, since on operation of the contractile drive 1 thedifferent layers of the hose wall have to move in opposite directionsand may thus bear against the connecting pin.

The term “connecting pin” is only to mean connecting elements, whichextend through adjacently placed hose sections. Their cross section doesnot have to be circular as in the working embodiment.

In order to brace the hose sections 18 and 19 a staple arrangement couldbe placed around them. Same could also be a component of the forceoutput means 8.

Departing from the design depicted in the drawing it is possible for theterminal regions 5 and 6 to be bent over several times so that more thantwo hose sections are adjacent to each other. Bending over once leadingto two adjacent hose sections 18 and 19 is however regarded as beingparticularly advantageous.

Between the adjacently placed hose sections 18 and 19 an intermediatepart could be arranged, by which the hose sections 18 and 19 are thenbraced as a further advantage. Such an intermediate part could be acomponent of the force output means 8.

1. A fluid power contractile drive comprising a contractile hose, in the case of which when there is a fluid actuation of an actuation space delimited by it a longitudinal contraction thereof takes place and which at its two terminal regions is adapted to be, or is, provided with a force output means rendering possible output of the drive force produced, characterized in that the contractile hose has a flat configuration at least at one terminal region and is bent over, the hose sections arranged adjacent to each other owing to the bending, of the hose sections of the contractile hose being firmly connected with each other.
 2. The contractile drive as set forth in claim 1, characterized in that the adjacently placed hose sections rest flatwise against each other.
 3. The contractile drive as set forth in claim 1, characterized in that the adjacently placed hose sections are firmly thrust together clamping means.
 4. The contractile drive as set forth in claim 1, characterized in that the adjacently placed hose sections are firmly connected together by a bond or a weld.
 5. The contractile drive as set forth in claim 1, characterized in that the adjacently placed hose sections joined together by a stitched seam connection firmly.
 6. The contractile drive as set forth in claim 1, characterized in that the adjacently placed hose sections are pinned together by means of at least one connecting pin extending through them.
 7. The contractile drive as set forth in claim 6, characterized in that the at least one connecting pin is constituted by a screw or a rivet.
 8. The contractile drive as set forth in claim 1, characterized in that the force output means associated with the at least one terminal region of the contractile hose is interlockingly connected with such terminal region.
 9. The contractile drive as set forth in claim 1, characterized in that the force output means associated with the at least one terminal region of the contractile hose possesses at least one connecting pin extending through the adjacently placed hose sections while simultaneously connecting same.
 10. The contractile drive as set forth in claim 9, characterized in that the at least one connecting pin possesses a screw thread rendering possible output of force.
 11. The contractile drive as set forth in claim 9, characterized in that the contractile hose possesses a hose body including a rubber elastic material and a tensile fiber arrangement which is coaxial in relation to the hose body and is preferably embedded in the wall of the hose body.
 12. The contractile drive as set forth in claim 11, characterized in that the tensile fiber arrangement comprises tensile fibers in a criss-cross array.
 13. A contractile hose for a fluid power contractile drive, characterized in that it possesses a flat configuration at one terminal region at least and is bent over, the hose sections produced by being bent over, of the contractile hose being firmly connected together.
 14. (canceled) 